Silicon powder is silicon that has been ground into a finely powdered dust. Depending on the purity of the silicon powder, it can be used for many purposes. It can be sintered, alloyed with metals to harden the mixture, made into microchips, used as a reactant in silicon compounds, or used in glass plasma deposition. Powdered silicon usually is made without any additional elements, but it can be mixed with elements such as carbon or oxygen to create different powders.
Silicon is the second most abundant element on Earth and, as such, has been used for many purposes. Unlike many other powders commonly used in metallurgy, silicon is not a metal but a metalloid, or an element that has metal-like properties but is not technically a full metal. Its lack of metal status means silicon powder is not made the same as metal powders are. The typical way of turning silicon into fine powder is to use industrial grinders to pulverize the material to a certain grade, depending on the powder’s intended use.
There are different purity levels of silicon powder, with lower levels having trace inclusions of other elements. The lower level of purity is around 98.5 percent and is mostly used by metallurgists as an alloying material to harden metals such as iron and aluminum. Chemists also use this as a reactant material in organic silicon mixtures and compounds. Higher-level purities, around 99.9 percent and 99.99 percent, are used in glass plasma deposition, or depositing silicon vapor onto a substrate to coat it with silicon.
The use of silicon powder by metallurgists is not limited to alloying; it can also be used in sintering. Silicon sintering is the process of pushing the powdered silicon into a cast and then heating it until the powder becomes a solid. Silicon, as both a powder and a solid, also is used in many electronics, such as in computer microchips and semiconductor parts. Powdered silicon also is used to manufacture solar energy cells.
Silicon powder commonly is made without the inclusion of other materials, but there are several popular mixtures that use other elements. Silicon dioxide is the mixture of silicon and oxygen and is used commonly to coat glass and to create glass under extreme heat and pressure. Silicon carbide, which combines silicon and carbon, is used in making ceramics, bulletproof vests and vehicle parts such as brakes and clutches.